I just bought a Taranis X9D plus two weeks ago, so it is brand new.
When turned on, I have a continuous weak but annoying humming sound noise coming out from the speaker.
My other Taranis X9D (not plus) bought 5 years ago does not make that humming noise and is still working well.
When I touch the antenna of the new Taranis plus, the humming noise decreases but is still there.

Any idea how to minimize this or eliminate it? None of my sound settings are at max, all 50% or less.

This problem is probably caused by RF crosstalk on the cables harnesses inside the Taranis.
I have to change my joysticks anyway so I will add a small ferrite or two to the culprit cables.
Or simply move a cable just a little bit inside will at least diminish the noise.

When I bought my Taranis plus I had the standard joysticks and the humming noise reported in this thread.
When I opened my Taranis plus to change the joysticks, I saw one ferrite and the big capacitor mod on DC power already applied but the noise was still present.

I changed my two joysticks to M9 hall effect joysticks and now the noise is reduced significantly to a point I need to put my ear near the speaker to hear the noise. So the buzzing is almost gone and is now very very weak.

That might be caused by the fact we don't have potentiometers to pick up RF noise and the hall effect joysticks reduce the electrical feedback noise.
Interesting.

It's ok to have some bugs but what I don't understand is that FrSky did not solve that problem with the recent units of Taranis and Taranis plus after all these years.
I just bought a new X9D plus and it still has the noise problem.
Q X7 does not have this problem so why don't FrSky correct it on the latest X9D units?

I hope there is no hidden problems in the radio transmitting hardware.

The only think that bugs me is that when the Tx is close by to X type receivers (not D types), we have this annoying telemetry lost/telemetry recovered.
I understand this is caused by a very strong signal that probably saturates the RF link but nevertheless it should be easy to solve (in my opinion).
Am I wrong? Probably